1. Field of the Invention
The present invention relates to equipment for use in a material size reduction process, and more particularly, it concerns an improved stationary peg for use in a grinding chamber of a rotary coal pulverizer.
2. Background of the Related Art
In operations that use coal for fuel, finely-ground coal particles or “fines” are required for efficient operation, yielding higher combustion efficiency than stoker firing, as well as rapid response to load changes. Using coal fines for combustion also produces less nitrous oxide (NOX) emissions and keeps oversized loss-on-ignition (LOI) unburned coal particles from contaminating the marketable ash byproduct of the combustion chamber. Thus, it is common practice to supply raw coal to a device, such as a pulverizer, that will reduce the size of the coal to particles within a desirable range prior to being used for combustion.
Many pulverizers employ systems and methods including one or more crushing and grinding stages for breaking up the raw coal. For example, in a rotary pulverizer, the coal particles are reduced to dust fine enough to become airborne in an air stream swept through the pulverizer by a gradual process that includes crushing the coal by repeated crushing actions of swing hammers and grinding the coal by attrition caused by rotating elements. The dust particles are entrained in the air stream and carried out for combustion.
It should be readily apparent that the process of reducing solid coal to acceptably sized fines requires equipment and components of high strength and durability. Therefore, there exists a continuing need for components that can reduce solid coal to acceptably sized fines and yield greater overall efficiency by withstanding extremely harsh conditions and causing less operation downtime due to maintenance and repairs.